Absolute cross sections for single-electron transfer of neon induced by C3+ at intermediate velocity (2.2v0—4.2v0) were measured and calculated using n-body classical trajectory Monte Carlo (nCTMC) method. Good overall agreement between experimental and nCTMC results is found. Screening effect, changes of the ionization potential and the effective charge are taken into account in interpreting the qualitative differences between theoretical and experimental results. In addition, the mechanism of transfer ionization is discussed briefly.